Use bucklets-provided constant to refer to Plugin API

Since the introduction of the standalone Buck build (see [1]), the
reference to Gerrit Plugin API need to be made using the
constant GERRIT_PLUGIN_API rather the explicit name, which
would cause tree vs. standalone conflicts problems.

[1] https://gerrit-review.googlesource.com/#/c/68224/

Change-Id: Ie1cbf2d8b140b2d3e87d356ef99ba9c23f1856b0
2 files changed
tree: daaae04c78af6cf61806ffeb73d27d4d186b4563
  1. lib/
  2. src/
  3. .buckconfig
  4. .gitignore
  5. BUCK
  6. LICENSE